RESUMO Foram conduzidos 4 experimentos em laboratório, 3 em casa-de-vegetação e 3 em campo, com o fim de avaliar a eficiência de fungicidas, em tratamento de sementes de trigo, para o controle de Pyricularia grisea Sacc, forma anamórfica de Magnaporthe grisea (Hebert) Barr, e Bipolaris sorokiniana (Sacc.) Schoemaker (Helminthosporium sativum Pammel, King & Bakke), forma anamórfica de Cochliobolus sativus (Ito & Kurib.) Drechs.: Dastur. Sementes das cultivares Anahuac e Batuíra foram tratadas com 20 fungicidas, em quatro fases consecutivas, e analisadas para sanidade, em laboratório, pelo método “deep-freezer”. Nos experimentos de casa-de-vegetação foram avaliados a emergência e os sintomas nas plântulas; em campo, além desses parâmetros, foi avaliada a produção. De acordo com os resultados obtidos, a maioria dos fungicidas foi eficiente para controlar os dois fungos. Os produtos avaliados, nas doses abaixo indicadas (g.de i.a. /100 kg de sementes) podem ser colocados em 4 grupos, em ordem decrescente de eficiência para controle de P. grisea e H.sativum em sementes de trigo: 1° grupo - iprodione+carbendazin (52,5+26,2), carbendazin+mancozeb (50+160) e triflumizole+tiofanato metílico (45+135); 2° grupo - iprodione + thiram (50+150) e carboxin + thiram (93,7+93,7); 3° grupo - iminoctadine (62,4), thiram (210), prochloraz (50) e carboxin+prochloraz (82,5+22,5); 4° grupo - triadimenol (67,5), guazatine+imazalil (60+4) e prochloraz (40). Thiabendazol (60), benomyl (125) e tricyclazol (75) controlaram eficientemente P.grisea, porém não controlaram B. sorokiniana, enquanto que flutriafol (7,5) e etiltrianol (4,9), que foram eficientes no controle deste fungo, não controlaram P.grisea. Foi obtida correlação negativa significante entre incidência de B. sorokiniana nas sementes e emergência, e positiva entre emergência e produção; não houve, entretanto, correlação significativa entre incidência de P.grisea e emergência. Este fungo foi transmitido pelas sementes de acordo com uma taxa (incidência nas sementes/n°de plantas com sintomas) que variou de 7,3:1 (13,6%) no inverno para 1,8:1 (55,5%) no verão, o que mostra a influência da temperatura sobre a transmissão do fungo. laboratório casadevegetação casa vegetação campo trigo Sacc Hebert (Hebert Barr Sacc. (Sacc. Helminthosporium Pammel Bakke, Bakke , Bakke) Ito Kurib. Kurib Drechs. Drechs Dastur 2 consecutivas sanidade deepfreezer. deepfreezer deep freezer . “deep-freezer” plântulas parâmetros produção obtidos fungos g.de gde g ia i i.a 100 /10 grupos P Hsativum H 1 iprodionecarbendazin carbendazin 52,5+26,2, 525262 52,5+26,2 52 5 26 (52,5+26,2) carbendazinmancozeb mancozeb 50+160 50160 50 160 (50+160 triflumizoletiofanato triflumizole tiofanato 45+135 45135 45 135 (45+135) 50+150 50150 150 (50+150 93,7+93,7 937937 93 7 (93,7+93,7) 62,4, 624 62,4 62 (62,4) 210, 210 (210) (50 carboxinprochloraz 82,5+22,5 825225 82 22 (82,5+22,5) 67,5, 675 67,5 67 (67,5) guazatineimazalil guazatine imazalil 60+4 604 60 (60+4 40. 40 (40) 60, (60) 125 (125 75 (75 Pgrisea B 7,5 (7,5 4,9, 49 4,9 9 (4,9) houve entretanto sementesnde n 7,31 731 7,3 7,3: 13,6% 136 13 6 (13,6% 1,81 181 1,8 8 1,8: 55,5% 555 55 (55,5% verão (Sacc “deep-freezer 10 /1 52526 52,5+26, (52,5+26,2 50+16 5016 16 (50+16 45+13 4513 (45+135 50+15 5015 15 (50+15 93,7+93, 93793 (93,7+93,7 62, (62,4 21 (210 (5 82,5+22, 82522 (82,5+22,5 67, (67,5 60+ (60+ (40 (60 12 (12 (7 7, (7, 4, (4,9 31 73 13,6 (13,6 81 18 1, 55,5 (55,5 / 5252 52,5+26 (52,5+26, 50+1 501 (50+1 45+1 451 (45+13 93,7+93 9379 (93,7+93, (62, (21 ( 82,5+22 8252 (82,5+22, (67, (4 (6 (1 (4, 13, (13, 55, (55, 525 52,5+2 (52,5+26 50+ (50+ 45+ (45+1 93,7+9 937 (93,7+93 (62 (2 82,5+2 825 (82,5+22 (67 (13 (55 52,5+ (52,5+2 (45+ 93,7+ (93,7+9 82,5+ (82,5+2 52,5 (52,5+ (45 93,7 (93,7+ 82,5 (82,5+ 52, (52,5 93, (93,7 82, (82,5 (52, (93, (82, (52 (93 (82 (9 (8
ABSTRACT Laboratory, greenhouse and field experiments were carried out in order to evaluate the effectiveness of fungicides, in wheat seed treatment, to control Pyricularia grisea Sacc., anamorphic state of Magnaporthe grisea (Hebert) Barr and Bipolaris sorokiniana (Sacc.) Schoemaker (Helminthosporium sativum Pammel, King & Bakke), anamorphic state of Cochliobolus sativus (Ito & Kurib.) Drechs.: Dastur. Seeds of Anahuac and Batuíra cultivars were treated with 20 fungicides, in four consecutives fases, and analised for health, in laboratory, by the deep-freezer method. In greenhouse, emergence and seedlings symptoms were evaluated; in the field, besides these parameters, yield was also evaluated. According to the results obtained, most of the fungicides were efficient for controlling both fungi. The products evaluated, in the doses below (g of a.i./100 kg seeds) can be put in 4 groups, in decreasing order of effectiveness for the control of P.grisea and B. sorokiniana in wheat seeds: 1° group - iprodione+carbendazin (52,5+26,2), carbendazin+mancozeb (50+160) and triflumizole+methyl tiophanate (45+135); 2° group - iprodione+thiram (50+150) and carboxin+thiram (93.7+93.7); 3° group - iminoctadine (62.4), thiram (210), prochloraz (50) and carboxin + prochloraz (82.5+22.5); 4° group - triadimenol (67.5), guazatine+imazalil (60 + 4) and prochloraz (40). Thiabendazole (60), benomyl (125) and tricyclazol (75) controlled efficiently P.grisea, but did not control B. sorokiniana while flutriafol (7.5) and ethyltrianol (4.9), that were efficient to control this fungus, did not control P.grisea. There was a significant negative correlation between H. sativum seed incidence and emergence and a positive correlation between emergence and yield. Nevertless, there was no correlation between P.grisea seed incidence and emergence. This fungus was transmitted by seeds in a transmission rate (seed infection/seed transmission) which ranged from 7.3:1 (13.6%) in the winter, to 1.8:1 (55.5%) in the summer, that indicates the influence of the temperature on its seed transmission. Laboratory treatment Sacc Sacc. Hebert (Hebert (Sacc. Helminthosporium Pammel Bakke, Bakke , Bakke) Ito Kurib. Kurib Drechs. Drechs Dastur 2 fases health laboratory deepfreezer deep freezer method evaluated parameters obtained fungi g ai100 ai i 100 a.i./10 groups Pgrisea P B 1 iprodionecarbendazin iprodione carbendazin 52,5+26,2, 525262 52,5+26,2 52 5 26 (52,5+26,2) carbendazinmancozeb mancozeb 50+160 50160 50 160 (50+160 triflumizolemethyl triflumizole methyl 45+135 45135 45 135 (45+135) iprodionethiram 50+150 50150 150 (50+150 carboxinthiram 93.7+93.7 937937 93 7 (93.7+93.7) 3 62.4, 624 62.4 62 (62.4) 210, 210 (210) (50 82.5+22.5 825225 82 22 (82.5+22.5) 67.5, 675 67.5 67 (67.5) guazatineimazalil guazatine imazalil 60 (6 40. 40 . (40) 60, (60) 125 (125 75 (75 7.5 (7.5 4.9, 49 4.9 9 (4.9) H Nevertless infectionseed infection 7.31 731 7.3 7.3: 13.6% 136 13 6 (13.6% winter 1.81 181 1.8 8 1.8: 55.5% 555 55 (55.5% summer (Sacc ai10 10 a.i./1 52526 52,5+26, (52,5+26,2 50+16 5016 16 (50+16 45+13 4513 (45+135 50+15 5015 15 (50+15 93.7+93. 93793 (93.7+93.7 62. (62.4 21 (210 (5 82.5+22. 82522 (82.5+22.5 67. (67.5 ( (40 12 (12 (7 7. (7. 4. (4.9 31 73 13.6 (13.6 81 18 1. 55.5 (55.5 ai1 a.i./ 5252 52,5+26 (52,5+26, 50+1 501 (50+1 45+1 451 (45+13 93.7+93 9379 (93.7+93. (62. (21 82.5+22 8252 (82.5+22. (67. (4 (1 (4. 13. (13. 55. (55. a.i. 525 52,5+2 (52,5+26 50+ (50+ 45+ (45+1 93.7+9 937 (93.7+93 (62 (2 82.5+2 825 (82.5+22 (67 (13 (55 a.i 52,5+ (52,5+2 (45+ 93.7+ (93.7+9 82.5+ (82.5+2 52,5 (52,5+ (45 93.7 (93.7+ 82.5 (82.5+ 52, (52,5 93. (93.7 82. (82.5 (52, (93. (82. (52 (93 (82 (9 (8